Pump fiston



Patented 3, 1922.

than" PATENT i ortica] JAMES W. GHILSON, OIE' DAYTON, IOWA.

PUMP PISTON.

Application filed July 6, 1820.

To all whom t ymay concern.' i f Be it known that l, JAMES W. CnILsoN, a citizenof the United States, and a resident of Dayton, in LAthe county of l/Vebster and State of Iowa, have invented a certain new and useful Pump Piston, of which the following is a specification.

The object of my invention is to provide a piston for pumps or the like of simple, durable and inexpensive construction.

More particularly it is my object to provide a pair of washer members, having inclined coat-ting surfaces thereon and a pliable-plate or strip of material placed therebetween and adapted to be moved to various positions, due to the upward and downward stroke of the piston.

Still a further object is to provide in such a device, a pliable strip of material held between a pair of coacting washer members or guides, the parts being so arranged that when the piston is moved downwardly, in

order to cause air to be ejected from the pump or the like, the back pressure will cause the pliable strip of material to `be forced outwardly at all points against the inner surfaces of the pump or cylinder.

With lthese and other objects in view, my invention consists in. theiconstruction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set fort-h pointed out in my claims and illustrated in the accompanying drawings, in which- Figure 1 shows a vertical, central, sectional view taken through a portion of a pump or cylinder with my improved piston member shown in cross section; and

Figure 2 shows a horizontal, central, sectional view taken on line 2--2 of Figure 1.

In the accompanying drawings, l have used the reference numeral 10 to indicate an ordinary pump cylinder, which is provided with the piston rod 11, which is formed with a contracted portion 12 near its lower end.

The contracted portion 12 is provided with the screw-threaded end 13.

My improved piston comprises an upper washer member 14, which is provided with a central opening 15 of substantially the same diameter as the contracted portion 12 of the piston rod 11. The washer member 14 is provided with an upwardly and outwardly extending annular flange 16` which forms the inclined surface or edge 17,

Serial Nm 394,313.

A second or lower washery member 13, which is provided with a central opening 19, is received on the contracted portion 12 of the piston rod 11. The washer member 13 is provided with an annular flange 20, which is also provided with an inclined surface, which is substantially formed at the same angle of inclination as is the inclined portion 17 of the washer 14.

Received between the washers 14 and 18 is the strip or di'scof pliable material 21, which maypreferably be made of leather or of some other material, which is easily moved to various positions and capable of conforming to the contour of any surface which it may be placed adjacent to.

The pliable material 21 is provided lwith a downwardly extending flange portion 22 and the upwardly inclined extending portion 23. The portion 23 isreceived between the inclined surface 17 of the washer 14 and the coacting inclined portion 2O of the washer 18.

The overall diameterof the washer 14 is substantially greater than the diameter of the washer 18.` The `purpose of this is to provide 'airinclined surface on which the pliable material 21 may conform to, when there is a great amount of pressure applied. to the under side of the piston.`

'ln Figure` l of the drawings, the dotted .lines `indicate the position of the pliablematerial 21 on the `downward strokeiof the piston or in the direction indicated by the arrow 25.

lt will be understood. that the air pressure on the downward stroke of the piston will cause the pliable material 21 at the flange 22 to be moved or forced outwardly at all points against the inner surface of the wall of the cylinder 10. The pressure will also cause the inclined portion 23 of the pliable material 21 to conform to the inclined surface 17 of the washer 14, thus tendingr t0 cause the flange 22 and the pliable material 21 to be moved outwardly as far as possible, thus forming an absolute air retaining compartment between the lower side of the cylinder 10 and the piston.

Received on the screw-threaded portion 13 of the piston rod is the nut 24, which holds the three parts which form the piston, namely, the washers 14 and 18 and the pliable material 21, against each other.

The contracted portion 12 of the piston j rod 11 forms a shoulder against which the upper surface of the washer 14 will rest, thus holding'the piston substantially rigid onto the piston rod 11.

It will be understood that the important parts of my device are the coacting inclined surfaces and the pliable material, which is capable ot easily conforming to the contour of inclined surfaces, in order to cause the pliable material to be forcedv outwardly at all points, due to the back pressure of the pump',v 'thus yforming a washer or piston capable of retaining air'and preventing it from leaking.:

is shown in Figure 1, the lower end of the cylinder is the end toward which the piston mores on its compression'stroke. As illustrated in this ligure, it will be noted that the washer 14 has its' ilange extending outwardly and upwardly, and it will' be also noted that the disc of pliable material 21 hasV portion spaced from its periphery that extends upwardly and outwardly, and then itsperipheral yportion extends straight downwardly" approximately parallel with the sides of the cylinder. By this arrangement, when the piston is making its compression stroke the pressure ott-he air between the downwardly 'etending portion 22 and the periphery of the washer 18 will cause the upwardly and' outwardly extending part23 of the disc v2.()hoi pliable material to wedge between therinclined flange 160i the washer 14; and the adjacent portion of thel cylinder, thus orcingth'e upper part of the fla-nge 22 out against the cylinder by the combined actio'nof the air pressure outwardly and the action ot the airpressure forcing the adjacent portion ot the pliable disc upon the inclined portion 16 of the washer 14. In other words, the lower part of the flange 22 is forced outwardly against'the cylinder by the air pressure 'aloneg'and the upper part of the flange' 22 is'forced outwardly against the cylinder by the air pressure upon the pliable disc forcing it against the inclined surface 16, which causes the upper portion of the said flange 22 to also move outwardly and upwardly until it is forced against the interior of the cylinder.

Some changes may be made in the construction and arrar gement oi' my pump piston, without departing from the essential Yfeatures and purposes of my invention, and it is my intention to c ver by my claim any modilied forms vof structure or use ot mechanical equivalents, which may be reasonably included within their scope.

' l claim as my invention: v

AA device of the class described, comprising a piston rod, two washers and a pliable disc mounted upon the said piston rod with the' pliable disc between them, the lower washer being provided at its periphery with a tflange, the outer portion ot the upper surface thereof being extended upwardly and outwardly, the periphery of the washer being substantially parallel with the piston rod, the upper washer having its periphery extendedupwardly and outwardly and the pliable disc having a portion near its periphery extended upwardly and outwardly, and its peripheral portion extended downwardly overlapping'the periphery ot the lower disc, and terminating near the lower edge of the lowerdisc and being free to move inwardly and outwardly toward and 'from vthe periphery of the lower disc, and whereby when'the piston ismoved downwardly the peripheral portionor" the pliable disc will be moved outwardly by the combined Aaction or" the resistance that .is being applied to the piston and its engagement with the inclined lperiphery of the vupper washer.

Des Moines, Iowa, June 16, 1920.

' JAMES lV. CHILSON. 

